Roland McGrath [roland@xxxxxxxxxx] wrote: | Yeah, that's fine. Since Oleg's pointed out that there is indeed no way to | avoid the leak in some global-init uses, it is fine to have a comment that | says that global init problems are part of the reason to outlaw this usage. | I just objected to a change that was really for container init but said it | was only to fix something different. Ok. How about this comment: --- Disable CLONE_PARENT for init. When global or container-init processes use CLONE_PARENT, they create a multi-rooted process tree. Besides siblings of global init remain as zombies on exit since they are not reaped by their parent (swapper). So prevent global and container-inits from creating siblings. Changelog[v3]: - [Roland, Oleg] Simplify comment describing the change Changelog[v2]: - Simplify patch description based on comments from Eric Biederman and Oleg Nesterov. - [Oleg Nesterov] Use SIGNAL_UNKILLABLE instead of is_global_init() Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx> Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> --- kernel/fork.c | 10 ++++++++++ 1 file changed, 10 insertions(+) Index: linux-mmotm/kernel/fork.c =================================================================== --- linux-mmotm.orig/kernel/fork.c 2009-06-30 23:01:06.000000000 -0700 +++ linux-mmotm/kernel/fork.c 2009-07-01 17:29:09.000000000 -0700 @@ -974,6 +974,16 @@ static struct task_struct *copy_process( if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM)) return ERR_PTR(-EINVAL); + /* + * Siblings of global init remain as zombies on exit since they are + * not reaped by their parent (swapper). To solve this and to avoid + * multi-rooted process trees, prevent global and container-inits + * from creating siblings. + */ + if ((clone_flags & CLONE_PARENT) && + current->signal->flags & SIGNAL_UNKILLABLE) + return ERR_PTR(-EINVAL); + retval = security_task_create(clone_flags); if (retval) goto fork_out; _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
